This relates generally to imaging devices, and more particularly, to imaging devices with both visible and infrared imaging capabilities.
Modern electronic devices such a cellular telephones, cameras, and computers often use digital image sensors. Imagers (i.e., image sensors) may be formed from a two-dimensional array of image sensing pixels. Each pixel may include a photosensor such as a photodiode that receives incident photons (light) and converts the photons into electrical signals. Image sensors are sometimes designed to provide images to electronic devices using a Joint Photographic Experts Group (JPEG) format or any other suitable image format.
Imaging devices may be configured to capture images in both the infrared spectral range as well as the visible spectral range. Infrared imaging can be used for a number of different applications such as three-dimensional (3D) imaging, automatic focusing, and other applications. In conventional image sensors, however, it can be difficult to separate signals corresponding to infrared light from signals corresponding to visible light. If care is not taken, infrared light received by color pixels in the image sensor can degrade the quality of images captured in the visible spectrum.
An infrared cutoff filter is sometimes placed in front of the image sensor to prevent infrared light from striking the image sensor. In order to capture images in the infrared spectral range, a separate imaging sensor is used for infrared imaging. However, the use of two separate imaging sensors is costly and can add undesirable bulk to an electronic device.
It would therefore be desirable to be able to provide improved imaging devices for capturing images in the infrared and visible spectral ranges.